Manufacture of safety glass



June 11, 1935. c, w BQNNIKSEN 2,004,518

MANUFACTURE OF SAFETY GLASS Filed Sept. 25, 1933 I: Sheets-Sheet June 11, 1935. w, o N sE 2,004,518

MANUFACTURE OF SAFETY GLASS V mvmufoa June 11, 1935. w BONNKSEN 2,004,518

MANUFACTURE OF SAFETY GLASS Filed Sept. 25, 1955 3 Sheets-Sheet 3 mva'n'ron Patented June 11, 1935 2,004,518

UNITED STATES PATENT DFFICE 2,004,518 MANUFACTURE OF SAFETY GLASS Cyril Wilfred Bonniksen, Slough, England, assignor to Protectoglass Limited, London, England, a British company Application September 23, 1933, Serial No. 690,759 In Great Britain June 4, 1932 10 Claims. (CI. 49-81) This invention comprises improvements in or ath, parts b ing br ken away to Show the inrelating to the manufacture of safety glass. ternal construction;

It is an object of the invention to provide Figure 2 is a vertical section on the line 22 means for facilitating the assembly and manuf Fi ure 1; facture of safety glass in accordance with prior Flgllle 3 is a tail; United States specification Serial No. 627,502. Fi ure 4 shows a co lapsible b acket upon a In the said application there is described a l l g process for the manufacture of safety glass in Fi ure 5 is a horizontal section on the lin which sheets of glass covered with a cellulosic 55 of Figure 4, and material (for example celluloid) are immersed Figure 6 is a diagram of the fluid pressure 10 in a laminating bath of a high boiling point control apparatus. liquid which is a softener or plasticizer for celluhe ba h c sis s of a de p r c an ular tank upon the glass have become united together. ty glass. The sides taper outwards slightly The present invention comprises in apparatus towards the D as s n n i ure for the manufacture of safety glass the com- The k II is m f elvamzed iron and bination of a laminating bath, a vertically movscrewed to a stout WOOden a ng Secured able cradle to receive sheets of glass coated with to l basis of the ta k are ur b ass grids i3 By this means the introduction of the sheets n e een in its entirety but only the tops of without disturbance or air bubbles is greatly i other ri s are Vi l n h fi r The facilitated, side edges 15 of these grids are machined to a By disposing the sheets in a vertical or nearly m n n are carefully p d so as vertical position as above described the exposed to be parallel to one another. They serve to bath is approximately verticaL nel member I8 is hung from a rod 20 depending The cradle may go operat a leaf or from an Operating cylinder as best seen in mounted so as to equalize the pressure on the until it reachesthe bottom position as shown tributed over their glass-engaging surfaces. ggg g g g g g gg gg i' Section vthere The invention further relates to various conare secured to it bracket arm 22 i structional features as hereinafter described. 8 Wh ch pmJect forwardly from the cradle and then upwardly panying drawings in which the cradle at high u e 1 is a front el vation of a lami a ng 2:. The construction of the folding brackets position shown in chain can be seen in Figures 4 and 5 which illustrate the uppermost bracket 25. As will be seen, each side of the cradle section I6 is cast with a longitudinal recess 26 on the side of which are two pivoted pins 21, 28. To the two pins are pivoted two parallel links 29, 39 and the links are pivoted at 3|, 32 to the bracket arm 25. Below the links 29,39 when in the position shown in the drawings is "'2, lug 33 which supportszthe weight. It will be seen that the bracket arm can be swung up about the line position in Figure 4, where it is out of the way behind the surface of the cradle section' l6. The brackets 22, 23, 24, 25 are provided for the purpose of supporting sheets of glass and the folding brackets serve to support small sheets when the cradle is not required for larger sheets. then the folding brackets are moved into the lines in Figure 4 so as not to interfere with the glass on the cradle.

The surface of the cradle section l6 and also the surface'of the grids |3 which alternate with them on the back of the tank II are studded with spring plungers 34 disposed at uniform distances apart for the purpose of exerting a gentle spring pressure over the whole area of a piece of glassheld in the cradle during the operations i which operate but which are illustrate the preferred. manner of carrying the hereinafter described. A detail of the construction of one of the plungers, which are all alike, is shown in Figure 3 and it will be seen that they comprise a stein 35 at the back of the plunger proper, which stem passes through a hole in the cradle I6 36. Behind the head of the plunger 34 is a spring 31.

Within the laminating bath and close to the bottom thereof are a'series of brackets 49 which support a rockshaft'fl. Upon the rocksh ft there are pivoted a series of swinging grids 42 which each lie opposite one of the grids l3 or cradle sections |6. The swinging grids or leaves are provided with spring plungers 43 similar to the spring plungers 34 and they are adapted, when swung towards the cradles, to press upon the back of a compound glass sheet laid on the cradles to hold it under spring pressure in the laminating bath. The swinging grids, of which only two are fully seen in Figure 1, others being broken away or hidden by the front of the bath, are all united together by a galvanized steel bar 44 along their top edges and the bar 44 is connected by links 45 to rams 46 of operating cylinders 41. In'Figure 6 the swinging frame operating cylinders" are shown but not their connectionsto the frame.

In addition to the parts described there are suitable control elements the' construction of which forms no part of the present invention shown in Figure 6 in order to invention into effects These include a handoperated control valve 49 and a rotary valve 59 which is actuated by the rod 29 of the lifting cylinder 2|. .Qnly one of the cylinders 41 to close the folding leaves 42 against the cradle I6 is shown in Figure 6, this cylinder being a'double-acting cylinder provided with a pipe connection connected to of the cylinder, supply of pressure to which holds the leaves open and a pipe connection 52 connected to the front end of the cylinder, supply of pressure to which serves to close the leaves. The branches 53, 54 are connected links into the chain- If large sheets are to be supported may be.

or grid |3 as the case may be and is secured at the back by a split pin.

in pipe 56 is connected to and the cylinders to the other cylinders and operated simultaneously. Air is supplied to the pipes 52, 54 through a branch 55 from a main supply 56 and tends continuously to close the leaves, but when air at the same pressure is supplied through the branches 5|, 53 to the backs of the cylinders 41 the leaves are held open because of the larger area of the .back of thepiston in the cylinder 41 .compared with the area at thefro nt of the .piston, which is reduced by the ram 46. The main air supply pipe 56 goes to the operating valve 49 and when the handle 51 of this valve is in the position shown in the drawings air passes to the pipe 58 and thence through the shuttle valve 59 and pipe 69 to the pipes 5|,53, thus holding the leaves open. The shuttle valve 59 consists simply of a small piston-shaped valve located in a cylindrical casing and capable of being pushed by the air pressure either to the right or left hand end of the casing as the case The air supply through the pipe 58 pushes the shuttle valve to the left-hand end of the casing 59 in the conditions supposed in Figure 6.

A branch 6| from the pipe 58 enters a direction relay valve 62 which contains a shuttle member 63. The shuttle 63 is, pushed over to the right in the figure by the pressure and admits air to the pipe 64 which carries it through a ball of a non-return valve 66 to the underside of the cylinder 2| which controls the cradle. In the position of the parts shown in the drawings the piston of the cylinder 2| has therefore been slowly raised to its uppermost position and the cradle is therefore lifted out of the laminating bath.

In this position of the parts the operator can lay upon the brackets carried by the cradle sheets of glass in pairs, which have been coated upon one face with celluloid or other cellulosic material, the celluloided'faces of the glass sheets being towards one another. Upon moving the handle 51 over to the position indicated by the chain line, in Figure 6 the pipe 58 is connected to the. atmosphere by the valve 49 through the exhaust pipe 68 and the air pressure the pipe 69 which passes to the rotary valve 59. The rotary valve 59 is controlled by a lever 19 having a forked end which lies inthe path of 29 of the cradle cylinder 2|. In the position of the parts shown in the drawings the pipe 69 will be connected by the valve 59 to the pipe 12 connected to the shuttle valve 59. The pipe 58 being now connected to the atmosphere by the valve 49 the pressure in the pipe 12 will force the shuttle of valve 59 to the right hand position of Figure 6 and thus pressure will be admitted from the pipe 12 to' the pipe 69. This happens instantaneously upon the lever 51 of the I, valve 49 being moved into the position 61 and thus although the pipe 58 is now connected to the atmosphere pressure is maintained in the pipe 69 41 are held with the leaves 42 open. Owing to the action of the bleed valve 65 air slowly leaks out of the cylinder 2| through the pipe 64, direction relay valve 62 and branch 6| to pipe 58 and thus to the atmosphere. The cradle "3, therefore, is lowered slowly into the laminating bath at a rate determined by the bleed valve 65 and the glass becomes gradually immersed edgewise in the liquid in the laminating bath. Owing to the smoothness of this motion no air bubbles are occluded with the glass sheets and the celluloid becomes a pin 1| on the rodv gradually immersed in the softening liquid which pressure in the time delay reservoir 18 has fallen constitutes the laminating bath. The operator to a certain extent. The pressure in the time in laying the glass sheets on the brackets 22 delay reservoir begins to fall immediately the takes care to leave a slight space between the valve 49 has been reset by the cylinder 80 as opposed faces of the glass at the bottom and already described because the conduit is conthe pressure in the conduitsil, 53 therefore falls tion and the parts resume the position shown 15 to that of the atmosphere. Consequently the in Figure 6 in which the glass can be removed air pressure in pipes 52, 54 is able to push over from the elevated cradle and fresh glass placed the pistons in cylinders 41 and the leaves 42 are in position for a new cycle of operations.

closed against the cradles l6 and grids I3 bring- The softening liquid employed in this bath the glass are brought together while excess then to remove it from the bath, no attention 25 At the same time-that the lever 10 opens the when he moves the handle till he removes the conduit 12 to the atmosphere it connects the glass from the machine. conduits 69 to a conduit 7 5 which is connected I claim:-

of the shuttle valve 63 therein from that to which for lowering the cradle gradually into the liquid mosphere, as soon as a small pressure is built are located, which leaf is movably mounted so up in the branch 79 the shuttle valve 63 moves that it may be caused to approach the cradle over and seals the conduit 64 from the conduit after i si n of the glass and press the glass 40 6|. No further motion of the parts takes place he t together.

until the pressure in the time delay reservoir 2, Apparatus for the manufacture of safety 18 has risen to an adequate predetermined valueglass comprising a laminating bath, a vertically passes only slowly through the adjustable an interposed mass of plastic material and to of the celluloided interfaces. the cradle and between which the glass sheets A r tting cyl nd 89 is P v which is are located, which leaf is movably mounted so nnect d y a pist n d 8i and conn ting rod that it may "be caused to approach the cradle 32 t0 the handle 57 0f the Valve Pressllre after immersion of the glass and press the glass adequate o operate the r ttin c linder 80 will sheets together, the parts of the leaf which press restore the valve 51 to the position shown in upon th glass being yieldingly mounted. Fi ure 6. Ther setting cylinder 80 is supplied 3. Apparatus for the manufacture of safety 55 wi h air under pressure at the approp iate t m glass comprising a laminating bath, a vertically by a co 83 connected through valve 34 movable cradle to receive sheets of glass havin and pipe 85 to the t me d y reservoir an interposed mass of plastic material and to he Va ve 84 S d 011 its Seat by a Spring hold them in a non-horizontal position, means and is adjusted to lift when h Pressure in the for lowering the cradle gradually into the liquid ting cylinder 80 and the valve 49. is restored to after immersion of the glass and press the glass air under pressure through the conduit 60 to the glass comprising a laminating bath, a vertically b a c 5|, 53 of the cy inde 4 which ope movable vertical cradle to receive sheets of glass ate the leaves 42. Thus the glass is unclamped. having an interposed mass of plastic material 62 does not move over to the right into the posicradle, means for lowering the cradle gradually tion shown in dotted lines in Figure 6 until the into the liquid, upstanding slides in the lami- 7 4 2,004,518 I nating bath whereon the cradle is movably supthe bath at such time that-the hinged grid. is ported, said means for raising and lowering the retracted and the hinged grid may only be adcradle Comprising a vertical cylinder and piston vanced at such time as the cradle has. been above the'slides. fully lowered into the bath.

" 5 "5. Apparatus for the manufacture of safety 8. Apparatus for the manufacture of safety 5 glass comprising a laminating bath, a vertically glass comprising a laminating bath, a vertically movable cradle to receive sheets of glass having movable cradle to receive sheets ofglass having an interposed mass of plastic material and to an interposed mass of plastic material and to hold them in a non-horizontal position, means hold them in a non-horizontal position, means for lowering the cradlegradually into the liquid, for lowering the cradle gradually into the liquid 10 upstanding slides in the laminating bath wherebath and for raising it therefrom, slides in the v on the cradle is movably supported, said means laminating bath, said cradle constituting a grid for raising and lowering the cradle comprising movably supported upon said slides, andretracta vertical cylinder and piston above the slides, able vertically spaced apart brackets on said said cradle having brackets thereon located .cradle. v

above the level of the bottom of the cradle and 9. Apparatus for the manufacture of safety so movable as to be capable of being set outglass comprising a laminating bath, a vertically standing from the faces of the grid to support movable cradle to receive sheets of glass having the glass sheets and of being retracted behind an interposed mass of plastic material and to the glass supporting face of the grid to allow hold them in a non-horizontal position, means 20 room for the support of larger pieces of glass for lowering the cradle into the bath, upstandat. a lower level on the cradle. ing slides in the bath whereon the cradle is 6. Apparatus for the manufacture of safety movably supported,, s ai d means. for raising. and

glass comprising a laminating bath, a vertically lowering the cradlecomprising a vertical cylinmovable cradle to receive, sheets of glass havder and piston above the cradle, ,said cradle .being an interposed mass of plastic material and ing in the form of a gridand having thereon a to hold them in a non-horizontal position, plurality of vertically spaced apart brackets outmeans for lowering the cradle gradually into standing from the face'thereof whereby the the liquid bath, a hinged grid pivoted along its glass sheets are supported.

lower edge in the laminating bath, and fluid- 10. Apparatus for the manufacture of safety 6 pressure means for causing the hinged grid to glass comprising a laminating bath, a vertically be pressed toward the cradle. movable cradle having a plurality of vertically '7. Apparatus for the manufacture of safety spaced apart brackets thereon to receive sheets glass comprising a laminating bath, a vertically of glass having an interposed layer of plastic movable cradle to receivesheets of glass having material, means for lowering the cradle into the 35 an interposed mass of plastic material and to liquid, means for transposing the sheets from hold them in a non-horizontal position, means a position where they are separated to a posifor lowering the cradle gradually into the liquid tion of actual contact, and means for exerting bath, a hinged grid pivoted along its lower edge a uniform pressure, over the whole area of a in the laminating bath, fluid-pressure means for piece of glass heldin the cradle while -in the causing the hinged grid to be pressed toward 'bath, said last-mentioned means comprising a the cradle, and means to insure that the vertiseries of spring-backed plungers. cally movable cradle may only be lowered into 'CYRIL WILFRED BONNIKSEN. 

